Do you mean that when you buy PIZZA, the value of PIZZA increases over time?
Typically, yes. PIZZA value increases over time.
are there separate rewards from Hive and rewards from PIZZA Coin? Do you receive Hive Coin and PIZZA Coin together?
Yes, they give separate rewards if you stacked on liquidity pool (Swap. HIVE:Pizza). I recieved other 2nd layer tokens from it. Sometimes, they also give out Hive rewards.